The present invention relates to a process for the production of a support of a bearing arrangement for a body to be balanced in a balancing machine to determine the effect of unbalance in two measuring planes and to a support produced by this process. The support has an auxiliary shaft holding the component to be balanced in two planes as well as vibration force pickups and a relative position indicator for the determination of the unbalance fraction as a function of position and magnitude attributed to the individual planes.
In order to balance rotating components not having a shaft of their own such as turbine wheels, gear wheels, wheels of vehicles and grinding wheels, for example, a balance machine must be provided with an auxiliary shaft on which these components can be fastened for the balancing procedure. It is then not important whether the auxiliary shaft extends in a vertical or horizontal direction but, for such components, it is essential that they are inspected for unbalance, if possible, in a position in which they are later arranged in assembled state together with other components in a then complete machine or in which their unbalance can be simply corrected. For example, for grinding wheels and motor vehicle wheels, a horizontal auxiliary shaft arrangement may be advantageous, particularly when these balancing machines are employed for balancing such rotating elements after a certain time of operation, such as operation of the vehicle wheels or wear of the grinding wheels, for example.
In order to obtain a reliable bearing arrangement of the auxiliary shaft, this shaft is usually supported at two bearing sites whereby the end of the auxiliary shaft holding the body to be balanced projects beyond one bearing arrangement so that, as a result, a so-called over-mounted bearing arrangement of the component to be balanced is possible.
In measuring for unbalance, the component, firmly connected to the auxiliary shaft, is made to rotate and the actions of the mass forces of the unbalance present in the component are picked up by vibration converters arranged in the bearing planes of the auxiliary shaft. The mass forces of the unbalance are separately indicated for each plane by means of a relative position indicator so that for each plane, the required unbalance equalization can be conducted in the appropriate relative position and with the appropriate weight. In addition to vibration path pickups, vibration force pickups such as piezocrystals or strain measuring strips are particularly suitable as vibration converters.
In order to prevent measuring errors caused by the bearing arrangement, such auxiliary shafts or spindles must be supported very accurately which is connected with high adjustment expense. In particular, for spindles which are supported horizontally and are to hold an over-mounted component to be balanced, the influence of the cantilevered weight on measuring errors caused by improper bearing support should not be underestimated. Frequent adjustment steps must be conducted to determine whether such balancing machines can still be used, for example, in gasoline stations and repair shops with their very uneven operations. These types of bearing supports are individually bolted together with the housing of the balancing machine, containing, for example, the drive motor and the evaluation electronics. This results in measuring errors because of a different pretension of bearing support and housing as a function of the screw tightening moment. These types of screw connections also may loosen somewhat over time which influences the measuring accuracy.